WO 02/16827 discloses a luminaire having a lamp housing accommodating lamps of different color aspects. The lamps are surrounded by a reflector and a non-transparent, light-transmitting window. In the lamp housing, light of different color or color temperature is mixed. The window gives access to a reflector housing where further mixing is provided. A disadvantage of the luminaire disclosed in WO 02/16827 is that the color mixing is not completely uniform. Another disadvantage is that the color of the light leaving the luminaire can not be adjusted without affecting the uniformity of the color mixing.